The objective of the research is to examine the physicochemical basis of DNA-protein interactions with a focus on the mechanism of action of the enzymatic and binding proteins involved in replication, recombination and transcription. Specific objects of study will be the gene 5 protein from the bacteriophage fd (involved in replication and packaging of DNA), the gene 32 protein from T4 (involved in replication and recombination), the DNA unwinding protein from E. coli (involved in replication) and the phage-coded RNA polymerase from T7. By a combination of chemical modifications and physical probes it should be possible to determine changes in the conformation of the protein on binding, the functional residues involved in binding, and ultimately the structure of the complexes. The physical probes to be used are circular dichroism, 19F, 1H, and 31P NMR and electron spin resonance. The NMR methods are being used to determine structural relationships between various amino acid groups and the nucleotide bases in complexes of the DNA binding proteins with oligodeoxynucleotides of defined sequence. Isolation of double-stranded restriction fragments of T7 DNA 125 base pairs in length carrying intact promoters for T7 RNA polymerase are being used to study promoter binding and initiation. BIBLIOGRAPHIC REFERENCES: Coleman, J. E., Anderson, R. A., Ratcliffe, R. G. and Armitage, I. M. (1976) Structure of Gene-5 Protein - Oligodeoxynucleotide Complexes as Determined by 1H, 19F, and 31P Nuclear Magnetic Resonance, Biochemistry 15, 5419-5430. Coleman, J. E. and Armitage, I. M. (1977) Multinuclear NMR Applied to the study of the Solution Structure of Protein-Nucleotide Complexes, in "NMR in Biology", British Biochemical Society, Academic Press, in Press 1977.